1. Field of the Invention
The present invention relates to a spool-type selector valve configured such that a spool provided with a seal member made up of an elastic body slides in a valve hole of a valve body for switching a channel.
2. Description of the Related Art
Japanese Examined Utility Model Registration Application Publication No. 2-20539, which is Patent Document, describes a 5-port selector valve configured such that in a valve hole of a valve body provided with a supply channel communicating with the valve hole, output channels communicating with both sides thereof, and discharge channels communicating with a valve-hole end side of the output channels, a spool provided with an annular seal member made up of an elastic body is slidably fitted for switching a flow of a fluid by sliding of the spool. In the 5-port selector valve, the seal member is configured to ride onto a valve seat between the supply channel (input port) and the output channel (output port) in the valve hole from the output channel side, and a tapered face is formed at an end portion on the output channel side of the valve seat in relation with a bending angle of the seal member. Also, the seal member is configured to ride onto the valve seat between the output channel (output port) and the discharge channel (discharge port) from the output channel side, and a tapered face is formed at an end portion on the output channel side of the valve seat.
In the valve body provided with the above valve hole, since the tapered faces onto which the seal member rides are formed on both sides of the pair of the output channels, it takes labor to machine the valve hole in the valve body. That is, the tapered face needs to be machined by inserting a tool into the both side portions of the output channel inside the valve hole through an end portion of the valve hole, which requires skills and time for the machining and causes a rise in a manufacturing cost.
However, if the tapered face can be formed such that a diameter of the valve hole is gradually increased as it goes from the center part to the both end sides, riding onto the valve seat by the seal member is smoothened by the tapered face and at the same time, moldability and workability of the valve body are improved.